Essential Maintenance: All Authorea-powered sites will be offline 9am-10am EDT Tuesday 28 May
and 11pm-1am EDT Tuesday 28-Wednesday 29 May. We apologise for any inconvenience.

David Gareth Babb

and 8 more

The loss of multiyear sea ice (MYI) in the Arctic Ocean is a significant change that affects all facets of the Arctic environment. Using a lagrangian ice age product we examine MYI loss and quantify the annual MYI area budget from 1980-2021 as the balance of export, melt and replenishment. Overall, MYI area declined at 72,500 km^2/yr, however a majority of the loss occurred during two stepwise reductions that interrupt an otherwise balanced budget and resulted in northward contractions of the MYI pack. First, in 1989, a change in atmospheric forcing led to a +56% anomaly in MYI export through Fram Strait. The second occurred from 2006-2008 with anomalously high melt (+25%) and export (+23%) coupled with low replenishment (-8%). In terms of trends, melt has increased since 1989, particularly in the Beaufort Sea, export has decreased since 2008 due to reduced MYI coverage north of Fram Strait, and replenishment has increased over the full time series due to a negative feedback that promotes seasonal ice survival at higher latitudes exposed by MYI loss. However, retention to older MYI has significantly declined, transitioning the MYI pack towards younger MYI that is less resilient than previously anticipated and could soon elicit another stepwise reduction. We speculate that future MYI loss will be driven by increased melt and reduced replenishment, both of which are enhanced with continued warming and will one day render the Arctic Ocean free of MYI, a change that will coincide with a seasonally ice-free Arctic Ocean.